Cassava harvesting is highly labour intensive and a partially mechanized operation. Development of a separate cassava stem harvester and incorporation with available cassava digger enhance then harvesting efficiency. To optimize the stem harvester design, this study investigated the effect of blade thickness, approach angle and shear angle on specific cutting energy and cutting index. The treatment with 20oshear angle, 30o approach angle and 6mm thickness yielded the minimum specific cutting energy and best quality of cut cassava stem respectively.